Abstract:
After water extract, ethanol extract and polysaccharides， three Allium species, including A. fistulosum and A. ascalonicum, contents of polysaccharides in these three Allium species were determined by phenol-sulfuric acid method, and their antioxidant activities were evaluated by ABTS (2,2′-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) diammonium salt) and DPPH (1,1-diphenyl-2-picrylhydrazyl) assays. Average contents of polysaccharides in A. tuberosum, A. fistulosum and A. ascalonicum were 11.40%, 22.57% and 15.97%, respectively. Both ABTS· + and DPPH radical-scavenging capacities were dose dependent, and mathematical model based on dose-effect relationship had high goodness of fit. Antioxidant activities of water extract, ethanol extract were significantly better than those of polysaccharides. The three species exhibited different antioxidant capacities. Among them, antioxidant activities of A. tuberosum were higher. EC50 values of ABTS·+ radical-scavenging capacity of water extract, ethanol extract and polysaccharides from A. tuberosum were 27.46, 15.58, 2.05×103, respectively, and EC50 values of DPPH radical-scavenging capacity were 66.41, 25.48, 3.16×107, respectively. In particular, ABTS + radical-scavenging capacity of ethanol extract was relatively close to that of vitamin C(Vc). To sum up, antioxidant activities of ethanol extract and water extract from A. tuberosum were relatively high, which showed great potential for exploitation and utilization.
